The present invention relates to the furnace and refractory construction arts. The invention finds particular application in conjunction with rotary and carbottom furnaces, and will be described with particular reference thereto. However, it is to be appreciated that the invention may find application in other fields in which thermal stability is advantageous.
Heretofore, furnaces have been constructed with movable hearths to facilitate the loading and unloading of workpieces for heat treatment. To avoid excessive thermal loss, close tolerances in the spacing between the side walls of the furnace and the outer edges of the movable hearth were advantageous. However, the relatively high temperature gradients and temperatures of the furnace environment caused thermal expansion of the hearth. If the tolerances between the hearth and side walls were too small, they would detrimentally interact or even lock.
The present invention contemplates a new and improved hearth construction which overcomes the above-referenced dimensional stability problems and others.